Cross-Protection against Homologous Drift Variants of Influenza A and B after Vaccination with Split Vaccine

Publisher： Karger

E-ISSN： 1423-0100|50|1|58-62

ISSN： 0300-5526

Source： Intervirology, Vol.50, Iss.1, 2006-11, pp. : 58-62

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Abstract

The aim of this serological study was to demonstrate the extent to which antibodies react against subsequent drift variants, after vaccination with split vaccine (Fluarix^TM). Antibody titers have been determined by hemagglutination inhibition test (HI) against different influenza A and B drift variants in sera from three past multicenter trials. Individuals of two different age groups, i.e. 18–60 years and above 60 years, were enrolled. Vaccine components influenza A/H1N1 and influenza B of Fluarix^TM show a high degree of cross immunogenicity against subsequent homologous drift variants. The genetically more variable component influenza A/H3N2 shows somewhat lower protection rates. High levels of cross immunogenicity were found between the variants of influenza A/Panama/2007/99 (H3N2) and influenza A/Wyoming/3/2003 (H3N2). The results demonstrate that in situations where drift variants emerge too late to be included in the influenza vaccine formulation, the cross-protection conferred must be evaluated on a case-by-case basis.